In virtually all types of sporting endeavors for many years, conditioning played a relatively insignificant role in preparing athletes for various types of sporting events. The basic belief during these years was that countless repetitions of the exact motions performed in a sport or athletic event constituted the only effective way in which an athlete's performance could be improved. In some instances, an extent of conditioning was used to supplement actual participation in the mechanics of the sport. This conditioning normally took the form of calisthenics to maintain or enhance flexibility and an extent of running to enable an athlete to control fatigue. Later, it slowly became appreciated that speed, quickness, and acceleration are significant ingredients of nearly every type of athletic endeavor. It further became appreciated that these explosive reaction characteristics constituted a form of power. In mathematical terms, power equals force times velocity, which transfers to the strength of an athlete and the velocity, or speed, at which the strength is applied to execute a motion or combination of motions.
Armed with this extent of understanding, a degree of strength conditioning was introduced into the training facets of a number of sports. Strength conditioning was essentially a known activity which could be implemented primarily through the use of weights. This technology was employed to increase the strength or force component of athletic power with results which eventually became widely accepted and employed in virtually all sports.
The velocity, or speed, component of developing the power for running speed, quickness, and other explosive reactions remained largely neglected. It was a widely accepted belief that speed and quickness were an innate quality which athletes either possessed or did not possess. It was, therefore, presumed that nothing significant could be done to improve speed and quickness characteristics in a particular athlete. Only in very recent years has there been widespread knowledge that this premise was fallacious.
Technical analysis and testing which has taken place in recent years has demonstrated the possibility of improving an athlete's velocity, or speed, characteristics in the application of his strength. As a result, exercises were developed which tended to decrease the time between the eccentric, or lengthening, contraction of sports-active muscles and the concentric, or shortening, contraction of the muscles. This resulted in adoption of jumping, leaping, and bounding exercises which stressed decreasing the time between these muscular responses. For these purposes, training equipment, if any, which was employed normally involved boxes or platforms raised different distances off the ground, which assisted athletes in effecting these muscular responses. In other instances, a form of resistance, such as elastomeric cords, have been employed to provide an extent of resistance to the conduct of these exercises.
Another facet of the velocity, or speed, component of power which was slow to be recognized was that the central nervous system is significant in providing signals to the muscles, controlling their rate of actuation. In this respect, interest was focused on overspeed training for athletic movements, which endeavored to train athletes under conditions where running stride or other motion are compelled at overspeed, or a speed greater than the athlete's normal maximum, to effectively train the central nervous system to accept and institute a faster rate of actuation. Overspeed activities have been somewhat limited to areas such as running events in track and field, where by virtue of another runner or an elastic band or cable, a runner is forced to exceed the normal stride rate for a limited time period.
There has not, however, been any significant introduction of training equipment which is dedicated to activities which have become known as plyometric training. In particular, there have been few devices which endeavor to accomplish a decrease in the time between muscle concentric contraction and eccentric contraction and overspeed training to concurrently condition the central nervous system.